The Near-Fault Region Zoning And Near-Fault Velocity Pulse-Like Ground Motion Simulation

Ground motion near hypocenter or seismogenic fault has aroused widespread concern in the field of earthquake engineering due to its serious damage to long period structures. This thesis studies the near-fault region zoning and the simulation of near-fault velocity pulse-like ground motion to find parameter values used in artificial ground motion in near-fault region. The principle contributions of this thesis are:(1) 1296 earthquake ground motion records which includes 977 horizontal seismic records and 319 vertical seismic records have been gathered from the PEER strong ground motion database and other seismic web sites.(2) 19 seismic damage potential parameters were selected and calculated. Through analysis of correlation between the parameters, the linear correlation between seismic damage potential parameters are figured out.(3) According to the fault type, site type and magnitude range, the seismic records collected are classified into 20 groups (11 groups of vertical and 9 of horizontal). Parameters for near-fault region zoning are chosen to define the critical fault distance.(4) 124 velocity pulse-like ground motion have been identified and velocity pulse-like component in seismic records extracted with wavelet analysis. Through the statistical analysis, the empirical formula of pulse-like component’s period Tp, peak ground velocity PGV, the time of peak velocity and the distribution characteristics of pulse are proposed.(5) Based on the comparison of the pulse period Tp calculated by the method of wavelet analysis and the pulse period Tsv calculated by the method of response spectrum,the rang and influence factors of Tp/Tsv are highlighted.(6)Through the comparison of the power spectrum of pulse component and non-pulse component, a method for calculating the critical frequency is proposed. Based on the value of critical frequency, the relationship between the critical frequency and pulse period has been found.(7) A improced pulse model is present according to that proposed by Tian, so that the peak velocity of the low frequency pulse generated by this model is equal to the input parameter about peak velocity. High frequency component which is generated by using the standard response spectrum as the target spectrum stacks up with the low frequency pulse. Then the near fault velocity pulse-like ground motion is generated.